Q. 125.0( 2 Votes )

# A topper wire of cross-sectional area 0.01 cm is under tension of 20 N. Find the decrease in the cross-sectional area Young modulus of copper = 1.1 × 10^{11} N m^{-2} and Poisson ratio = 0.32.

Answer :

1.164 × 10^{-6} cm^{2}

Given, cross-sectional area,

Tension in the wire,

Young modulus of the wire,

We know, stress,

And strain is given by ,

Young’s modulus then becomes,

therefore, longitudinal strain becomes,

Let the circular cross-section be of diameter

Given, Poisson’s ratio

hence, lateral strain

We know, area is given by

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